In the processing of sheets or webs of flexible materials such as sheets or webs of paper or paper board or fabrics, including the operations of slitting, cutting and punching of the sheets or webs, it is common to generate small scrap pieces of the material such as edge trimmings and hole punchings. The scrap pieces are removed from the processing machinery by air suction conduits connected to the inlets of motor driven blowers. It then becomes necessary to separate the small scrap pieces of material from the air, and it is desirable to reclaim the air so that the air is not exhausted into the atmosphere, since this can result in the loss of substantial heat from a building. Usually, the small scrap pieces of material are separated from the air with the use of cyclone separators. The cleaner air flowing from the separators is then directed into filter bags, for example, of the type produced by Menardi-Criswell in Augusta, Ga., which remove dust and other small particles from the air.
It has been found that a significant number of cyclone separators are required to clean a high volume flow of air carrying scrap pieces of material. In addition, some of the smaller scrap pieces flow through the separators and collect in the bag filters, thus requiring frequent replacement of the filter bags. When filter bags are not used, it is common to exhaust the air with the entrained dust and small particles into the atmosphere, resulting in contamination of the atmosphere and significant energy loss for the building.